DFW

Dallas/Fort Worth is designed as five semicircular terminals (A through E) around a central spine, and unlike most US mega-hubs, the terminals here operate as one system connected by the Skylink train — which most travelers underuse. American Airlines occupies Terminals A, B, C, and most of D, so if you're on an American flight, your terminal is essentially assigned by aircraft rotation, not by where you booked from.

The DFW-specific quirk: American's afternoon connection bank at 4-6 PM is the single biggest wave, but it's spread across four terminals, which means no individual TSA checkpoint gets crushed the way it does at ATL or ORD. If you have PreCheck, the wait rarely exceeds 10-12 minutes even at peak. Without PreCheck, checkpoint choice matters — Terminal A checkpoints tend to move faster than Terminal C because A's traffic is more business-heavy.

Terminal D handles most international departures and virtually all customs traffic. It's the newest and most spacious of the terminals, and the food is materially better here than in the other four. If you're arriving early or have a long layover, walking (or Skylinking) to D even from A or C is worth the ten minutes — it's a completely different atmosphere.

Late-morning DFW (10 AM – 12 PM) is the quietest window of the day. The 6-8 AM local rush has cleared, the 4 PM connection bank hasn't ramped, and the airport feels almost sleepy despite being one of the busiest in the world. If you have any flexibility on booking, target a mid-morning departure — you'll thank yourself in the security line.